The present invention relates generally to bridging between segments of communication networks. More particularly it relates to the extension of bridges between segments of IEEE 1394 type serial bus networks.
In the prior art, an IEEE 1394 serial bus is capable of supporting only 63 nodes within one bus with all nodes sharing a common bandwidth resource, and in which any node generates bus resets affecting all other nodes. Inter-node distance is limited to a few meters in IEEE 1394a or several hundred meters in IEEE 1394b. The resulting limitation in scalability is partly alleviated by IEEE 1394 bridges segmenting an IEEE 1394 serial bus network into a maximum number of 1023 serial buses. The limited inter-node distance with a bus remains unaffected. A limitation to two-portal IEEE 1394 bridges may additionally lead to bandwidth bottlenecks within extended IEEE 1394 serial bus networks.
What is needed is an extension to IEEE 1394 serial buses that allows interconnection of IEEE 1394 serial buses over increased distances and improved scalability in terms of number of streams and/or bandwidth preserving the quality of service of native IEEE 1394 networks.
A different network technology known as Ethernet may provide improved connectivity. As described in an Oct. 13, 1998 presentation on IEEE 1394 by ControlNet, Inc. of Campbell, Calif.; Ethernet-compliant communications and packets may be transported over an IEEE 1394 network using ControlNet""s xe2x80x9cETHERWIRExe2x80x9d product and technology. However, such Ethernet-related technology known in the art cannot transport IEEE 1394-compliant communications and packets over Ethernet/802.3 products. For example, advantageous features of IEEE 1394 such as quality of service (QoS) are not provided by Ethernet, if not complemented by other methods.
A need exists for a bridging technology which provides the advantages of IEEE 1394 as well as the capability to transport IEEE 1394 communications and packets over Ethernet technology and/or IEEE 802.3 technology, referred to herein generally as xe2x80x9cEthernetxe2x80x9d.
The present invention complements Ethernet technology to provide the advantageous features of IEEE 1394 technology, by introducing the new concept of split IEEE 1394 bridges in which individual portals or bundles of portals communicate over a non-full featured IEEE 1394 network such as a local or wide area network and combines this with the concept of IEEE 1394 multi-portal bridges. This non-IEEE 1394 network is referred to herein as a xe2x80x9ccore netxe2x80x9d. Multi-portal bridges may be formed through the connection of several split bridges each with one or more IEEE 1394 portals over a core net. The core net is invisible to the IEEE 1394 nodes with respect to traffic originating from an IEEE 1394 bus for a destination in an IEEE bus. This new type of network elements allows for increased network scalability in both terms of physical size and levels of hierarchy. Useful properties of a core net such as availability of high-performance switches or increased reach are thereby incorporated into an IEEE 1394 network.
The invention additionally supports, where applicable, traffic originating from the IEEE 1394 network to be routed to a destination within the core net and vice versa. Network configuration, traffic separation, ingress control and resource signaling are performed to maintain quality of service (QoS) levels as in an IEEE 1394 serial bus network and, for packets originating from the core net and traveling into the IEEE 1394 network and vice versa, the quality of service of the originating network is mapped onto corresponding services within IEEE 1394. The presence of different network and protocol types is hidden in the case of nodes communicating to nodes attached to a network of the same kind. Through the use of an appropriate adaptation protocol, for example dedicated framing and segmentation/reassembly, isolated nodes contained within one protocol domain are enabled to communicate to the other domain as if it was the same domain. The invention supports dynamic insertion and removal of bridge portals to/from the core net.